AARP The Magazine features notables 50 and

Ralph Miller was not amused when he collected the mail that day in February. His 50th birthday was still several months away, but there it was: an AARP membership invitation.

The nerve!

Miller tore the offending letter in half without opening it and stuffed it in the garbage. Miller, a deputy sheriff for Orange County, is an accomplished athlete who has participated in 18-hour-long adventure races. He's too young, he says, for AARP.

Unlike Miller, Georgia Hightower was thrilled to receive her AARP notice. Old, young, who cares? Hightower never met a discount she didn't like.

Hightower, who is 51, had no qualms about joining AARP, the advocacy group for those 50 and older.

"I'll lie about my weight, but I'll tell the truth about my age," says Hightower, a sales associate for Mercury Printers & Promotions Inc. in Orlando. "I'm the last one to know I'm aging."

Hightower's twin brother, Robert Stuart, is somewhere in-between. Although he enjoys reading AARP The Magazine at his doctor's office, he's reluctant to join. The membership invitation, which landed in his mailbox when he was 49, was a not-so-subtle reminder that his birthday was on the horizon.

"You don't know that you've turned 50 till you get your first piece of mail from AARP," Stuart says.

Receiving that first AARP letter has become a societal milestone. Depending on the person, it can be an unwelcome reminder, a cause for celebration or a trigger for denial: Don't know how my name got on that list. Must be a mistake.

"It's becoming a rite of passage . . . a new normative experience," says Eric Kingson, professor of social work at Syracuse University. "It's a cultural demarcation of aging."

Like its constituency, the AARP has evolved with the times. In 1999, the organization changed its name from the American Association of Retired Persons to just AARP, in part because 46 percent of members still work.

And about 10 years ago, the group lowered the membership age from 55 to 50. Individuals need to start thinking about retirement earlier, says Kathy Marma, AARP spokeswoman.

AARP membership provides numerous discounts on everything from car rentals to cell phones. The oganization also offers auto and health insurance options and a voice in an advocacy organization.

Despite those benefits, Marma acknowledges that some might not relish receiving the membership invitation, but, "they get over that." Indeed, a third of members are under age 60. and the AARP begins to court potential members around age 49.5, Marma says.

(Of course, it doesn't always work out that way. At least one Orlando teenager received an AARP invitation by mistake but decided to defer membership.)

Regardless, these days 50 is considered middle age, and for many, even the half-century mark is not a momentous event.

"Some people have more of a crisis when they turn 30 than they do when they turn 50," says Margaret Young, professor of human development at Washington State University.

Life expectancy has reached 77.7, according to the Centers for Disease Control, and many expect to live well past that age.

"The older you get, the older you think `old' is," Young says.

A sampling of Young's college-age students defined "old" as 55 to 61. But 60-year-olds do not ordinarily think of themselves as old, Young says.

"They're living healthier, living longer, working longer, not just sitting home on the rocking chair or baking cookies for the grandkids," Young says.

But living longer also has introduced the possibility of living with chronic illnesses or disabilities -- conditions previous generations may not have survived. And that frightens some middle-aged folks who are reluctant to think about aging, says Patricia San Antonio, professor of sociology and anthropology at the University of Maryland.

"Maybe that's why it's such a shock to get the AARP thing at 50," San Antonio says. " . . . It's very shocking to think of yourself as being in that category."

But like it or not, an AARP letter is a positive sign, says Syracuse professor Kingson, because just about everyone aspires to live a long and active life.

Into the circular file

Since she turned 50, Vicki Brooks has been preparing to live an active life well into retirement.

Brooks, 57, describes receiving the AARP letter as a "wake-up call."

"When I turned 50, it was like exclamation points and different lights turning on," says Brooks, an administrator at Orange County Schools.

Brooks realized she needed to make some major decisions. She reassessed her goals, her investments, her insurance, her living conditions and her lifestyle. She planned for her retirement.

And she joined AARP.

Robert Randell, however, doesn't plan on signing up anytime soon.

Shortly after Randell turned 50, he competed in a triathlon.

"I'm probably in as good shape as I was when I was 30," says Randell, a pathologist and director of the blood bank at Florida Hospital.

So when he received mail from AARP, he says, "I was surprised and a little bit dismayed."

Randell's buddy Miller -- the deputy who promptly tore up his AARP notice -- expressed a similar sentiment.